The present invention relates to a gasket having a dry lubricant and, more particularly, to an elastomeric gasket for use in any system using an elastomeric gasket, for example, pipe couplings. The benefits of the present invention may be beneficially applied to any system in which a dry lubricant can be used to assist gasket seating and emplacement.
Numerous types of systems use gaskets to prevent leakage. For example, pipe couplings are known which are intended to economically and efficiently provide secure, leakproof connection at the juncture of a variety of pipe configurations. The particular coupling assembly selected naturally depends upon the type of pipes being connected, their routing, and their sizes, and the intended service for which they will be used.
Typical of such pipe couplings, in which the present invention has found particularly advantageous utilization, are the (i) groove pipe couplings as typically shown in the U.S. Pat. No. 4,601,495, (ii) the T couplings for branch pipes to be secured to a main pipe, as typically shown in U.S. Pat. No. 3,999,785, (iii) the cam actuated couplings, as typically shown in U.S. Pat. No. 4,165,892, and (iv) the boltless locking pin secured couplings as typically shown in U.S. Pat. No. 4,561,678, all of which are assigned to the assignee of the present invention and the disclosures of which are incorporated herein by reference.
While differing in construction and application, one common feature of all such couplings, as well as other coupling constructions to which the present invention is applicable, is the inclusion of a deformable gasket, which is typically constructed of an elastomeric compound, such as natural or synthetic rubber. The gasket is contained within a suitably configured recess and is employed to seal the pipes meeting at the coupling, to prevent leakage when the coupling is in an assembled condition.
Typically, when the various components of the coupling, including the gasket, are shipped to the installation site, the gasket is exposed to the environment. It has been found that during shipping, dust, or other contaminants, such as paint chipping off of the coupling segments, may stick to the gasket. At the site, the installer must then remove, clean, and lubricate the gasket during the process of installing the coupling joint onto the pipe.
In addition to the inefficiency of having to clean the gasket at the installation site, the polymeric water-based lubricants or the silicone-based lubricants which are currently applied to the gasket surfaces in the xe2x80x9cwet statexe2x80x9d at the installation site, tend to run, stain and, in general, leave an unsightly and unsafe residue. In many instances, the installer may either place a non-uniform or uneven quantity of lubricant, or even the wrong lubricant, on the gasket. This can ultimately result in leakage due to an improper gasket seal, as well as damaging the gasket and materially shortening its useful life. Safety can also be compromised by virtue of the slippery residue being transferred to tools, surfaces, and body parts.
Accordingly, it is an object of the present invention to provide a pipe coupling gasket having a dry lubricant in the form of a dry film bonded thereto.
It is another object of the present invention to minimize exposure of the gasket to oxidative effects by the encapsulating and permeability characteristics of the surface treatment.
It is a further object of the present invention to pre-lubricate an elastomeric gasket when it is manufactured by applying a lubricating film to its surfaces and which is in a dry condition during shipment and installation in a pipe coupling at a pipe assembly site.
It is still a further object of the present invention to provide an elastomeric gasket or seal, ready for installation in a pipe coupling, having pre-lubricated surfaces which are in a dry state.
It is yet a further object of the present invention to provide an elastomeric gasket or seal having a pre-lubricated dry surface which is colored or dyed to denote and verify the presence and coverage of the lubricant or its service rating.
These as well as other objects will become apparent upon review of the following drawing and detailed description which follows.